Endoscope with drying agent

ABSTRACT

What is described here is an endoscope including an endoscope optical system and a desiccant which is introduced into and fixed in the mounting space of the endoscope optical system. The invention excels itself by the provisions that the desiccant is present in the form of a plurality of spheres (5) and/or rod-shaped elements which are inserted into at least one recess (4) in the mounting space, and fixed by means of at least one fixing element which contacts the spheres or the rod-shaped elements merely over part of their surface.

DESCRIPTION

1. Field of the Invention

The invention relates to an endoscope with an endoscope optical systemand a desiccant introduced into and fixed in the mounting space of theendoscope optical system.

2. Prior Art

Endoscopes and particularly endoscopes employed in biomedicalengineering are fundamentally fluid-tight systems. For a number ofreasons, however, moisture may occur in the mounting space of theoptical system of the endoscope:

First, it is possible that due to the humidity of the air in the spacewhere the endoscope is assembled some residual moisture remains in themounting space of the endoscope. And secondly moisture may penetrateinto the mounting space through slight leaks at joints, which, actuallyspeaking, do not require an expensive repair of the endoscope.

For this reason it has been common for a major period of time already toprovide a desiccant in the mounting space of the endoscope opticalsystem for adsorption of this residual moisture.

Different solutions have become known for the incorporation of thedesiccant into the mounting space of the endoscope optical system:

One example is the provision of the desiccant in bulk form in themounting space. This approach presents the disadvantage, however, thatnoise will occur when the optical system is moved and that moreover dustmay be produced as a result of desiccant abrasion caused by movement.The dust may deposit on the optical elements.

The German Patent DE 37 08 124 C2 discloses an endoscope with ahydroscopic element wherein the hydroscopic element is designed asflexible strip material and mounted in a part of the endoscope opticalsystem between the lens carrier and the outer wall, which part isspecifically provided to this end. That known endoscope, which theintroductory clause of patent claim 1 starts out from, presents thedisadvantage that an exchange of the hydroscopic element is possibleonly upon complete disassembly of the endoscope.

The German Patent DE 195 07 205 A1 has therefore proposed the provisionof a hydroscopic substance underneath a removal wall element of hehousing, which is connected to the remaining parts of the housing wallin a gas-tight manner by means of a coupler. This design presents thedisadvantage that the endoscope has an opening wider than that whichmust be ensured to be fluid-tight.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is based on the problem of improving an endoscopewith an endoscope optical system and a desiccant which is introducedinto and fixed in the mounting space of the endoscope optical system, ina way that the desiccant will be reliably fixed in the mounting spaceand has a high moisture adsorption efficiency so that an exchange of thedesiccant is not required as a rule.

In accordance with the present invention the desiccant is present in theform of a plurality of spheres and/or rod-like elements which areinserted into at least one recess in the mounting space and which arefixed by means of at least one fixing element contacting the spheres orthe rod-shaped elements merely over one part of their surface.

With this design the invention starts out from the finding thatendoscopes must be suitable for disassembly for servicing reasons sothat it is not necessary to provide an additional opening for theexchange of the desiccant.

On account of the fixed mounting of the desiccant in the mounting spaceof the optical system it is not necessary for an exchange of thedesiccant to disassembly the endoscope beyond the measure common forregular servicing. Due to the provision of the desiccant in the zone ofthe eyepiece sufficient space is available for accommodating such anamount of desiccant that the desiccant quantity will be sufficient foran average service life of an endoscope. The desiccant may, of course,yet be exchanged whenever this will be necessary.

The use of a plurality of spheres and/or rod-shaped elements with apreferably cylindrical shape a large desiccant surface is achieved sothat a high efficiency in desiccant adsorption will be reached.

The fixing element serves the purpose of first reliably fixing thedesiccant, which is present in the form of spheres or rods of preferablycylindrical shape, and of secondly ensuring an unobstructed exchange ofair so that the desiccant may adsorb any moisture present in the spacewhere the optical system is mounted.

One advantage of the design is the major part of the desiccant surfacefree so that the moisture can be absorbed without any problems.Moreover, the O-rings may be replaced without any problems when thedesiccant is exchanged.

The use of a container having a wall permeable to moisture andconsisting particularly of a diaphragm ensures a reliable fixing even inthe event of vibrations etc.

Various possibilities exist for the desiccant such as silica gel orporous ceramic material. Such desiccants, which may produce the effectsof a molecular sieve in particular, are commercially available.

In an expedient improvement moisture-measuring means may be provided inthe space where the optical system is mounted. Based on the result ofmeasurement, the operator is able to determine whether the moisture inthe mounting space of the optical system is within the range ofacceptable limits. If an excessively high moisture is indicated thissituation may be due to an exhaustion of the desiccant so that thelatter must be exchanged, or whether the endoscope presents a leakthrough which moisture enters to an extent so high that it can no longerbe adsorbed by the desiccant.

The moisture-measuring means can preferably include a chromaticindicator wherein the colour changes reversibly or irreversibly at adefined moisture lever and which is visible in a window from theoutside. Such colour indicators are commercially available.

BRIEF DESCRIPTION OF THE DRAWING

The following is an exemplary description of the invention withreference to an embodiment, without any restriction of the generalinventive idea, with the single FIGURE of the drawing being referred towhich shows:

a cross-sectional view taken through the proximal part of an inventiveendoscope

DESCRIPTION OF AN EMBODIMENT

The proximal part of an inventive endoscope, which is illustrated in theFIGURE, comprises a flaring eyepiece mount 1 with an eyepiece coveringglass 2. The flaring eyepiece mount 1 is connected to a base part 3 ofthe endoscope in a manner known per se, which part is illustrated onlypartly. On the base part 3 the connector for a light guide is provided,for instance, which is not illustrated here.

Within the area of the eyepiece covering glass 2 a peripheral groove 4is provided on the base part 3 in accordance with the invention, intowhich the desiccant spheres 5 are inserted. These spheres 5 are retainedby an O-ring in order to prevent them from dropping out of the groove 4due to movements of the endoscope.

This arrangements presents a number of advantages:

the desiccant spheres 5 present a comparatively large surface availablefor adsorption;

the surface is "freely accessible" since the O-ring contacts the spheresonly over a comparatively small surface;

retrofitting of existing endoscopes to achieve the inventive embodimentis easily possible--by a replacement of the comparatively inexpensiveproximal part or by subsequent provision of the groove 4;

the inventive arrangement of the desiccant does not require anenlargement of the dimensions of the endoscope; and yet vignetting ofthe optical path for observation does not occur.

The moisture-measuring means, which is provided in a preferredembodiment of the invention and which is not illustrated in the FIGURE,may equally be provided in the base part 3. The window for observationof the result of measurement and particularly for observation of thecolour indicator whose colour undergoes a reversible or irreversiblechange at a defined moisture level, must, of course, be so disposed thatlight will not enter into the optical path for observation, which wouldproduce the effects of interfering stray light.

What is claimed is:
 1. Endoscope comprising an endoscope optical systemand a desiccant introduced into and fixed in a mounting space of theendoscope optical system, characterized in that said desiccant ispresent in the form a plurality of spheres which are inserted into atleast one recess in said mounting space and which are fixed by at leastone fixing element which contacts said spheres over only a portion oftheir surface.
 2. Endoscope according to claim 1, characterized in thatsaid at least one fixing element is an O-ring (6) which fixes saiddesiccant in said recess.
 3. Endoscope according to claim 1,characterized in that said at least one fixing element is a containerhaving a wall permeable to moisture.
 4. Endoscope according to claim 3,characterized in that the wall of said container consists of adiaphragm.
 5. Endoscope according to claim 1, characterized in that saidendoscope includes a flaring eyepiece mount, and in that said desiccantis arranged adjacent of the flaring eyepiece mount (1).
 6. Endoscopeaccording to claim 1, characterized in that said desiccant is a silicagel or a porous ceramic material.
 7. Endoscope according to claim 1,characterized in that a moisture-measuring means is provided in thespace where the optical system is mounted.
 8. Endoscope according toclaim 7, characterized in that said moisture-measuring means comprises acolour indicator whose colour undergoes a reversible or irreversiblechange at a defined moisture level, and is visible in a window from theoutside.
 9. Endoscope according to claim 1, characterized in that saidfixing element is so configured that said desiccant may be exchanged inthe course of regular endoscope servicing.
 10. Endoscope comprising anendoscope optical system and a desiccant introduced into and fixed in amounting space of the endoscope optical system, characterized in thatsaid desiccant is present in the form a plurality of rod-shaped elementswhich are inserted into at least one recess in said mounting space andwhich are fixed by at least one fixing element which contacts saidrod-shaped elements over only a portion of their surface.
 11. Endoscopeaccording to claim 10, characterized in that said at least one fixingelement is an O-ring (6) which fixes said desiccant in said recess. 12.Endoscope according to claim 10, characterized in that said at least onefixing element is a container having a wall permeable to moisture. 13.Endoscope according to claim 12, characterized in that the wall of saidcontainer consists of a diaphragm.
 14. Endoscope according to claim 10,characterized in that said endoscope includes a flaring eyepiece mount,and in that said desiccant is arranged adjacent the flaring eyepiecemount (1).
 15. Endoscope according to claim 10, characterized in thatsaid desiccant is a silica gel or a porous ceramic material. 16.Endoscope according to claim 10, characterized in that amoisture-measuring means is provided in the space where the opticalsystem is mounted.
 17. Endoscope according to claim 16, characterized inthat said moisture-measuring means comprises a color indicator whosecolor undergoes a reversible or irreversible change at a definedmoisture level, and is visible in a window from the outside. 18.Endoscope according to claim 10, characterized in that said fixingelement is so configured that said desiccant may be exchanged in thecourse of regular endoscope servicing.